Electric/dielectric properties of composites filled with onion-like carbon and multiwalled carbon nanotubes

Abstract

The dielectric/electric properties of polyurethane composites filled with carbon nanotubes (CNTs), onion-like carbon (OLC) and mixed onion-like carbon/carbon nanotubes are compared across a wide frequency range from hertz to terahertz. The highest value of dielectric permittivity and electrical conductivity is observed in composites with carbon nanotubes. However, the dielectric/electric properties of composites filled with onion-like carbon are also very attractive and can be improved by addition of small amounts of carbon nanotubes due to the strong synergy effect. In composites with inclusions of mixed onion-like carbon/ carbon nanotubes, the dielectric permittivity and electrical conductivity increase due to the decreasing of both the potential barrier for carrier tunneling and the average distance between nanocarbon clusters.